CI: upgrade rustc from 1.79 to 1.81 due to

```
error: rustc 1.79.0 is not supported by the following package:
  [email protected] requires rustc 1.81
```

updated snapshot test
ci: snapshot test again, by

```shell
TRYBUILD=overwrite cargo +1.81 test stack
```

Author: CGMossa

.github/workflows/nalgebra-ci-build.yml

@@ -64,7 +64,7 @@ jobs:
       - name: Select rustc  version
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.79.0
+          toolchain: 1.81
           override: true
       - uses: actions/checkout@v4
       - name: test

nalgebra-sparse/src/coo/coo_serde.rs

@@ -4,7 +4,7 @@ use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 /// This is an intermediate type for (de)serializing `CooMatrix`.
 ///
 /// Deserialization requires using a `try_from_*` function for validation. We could have used
-/// the `remote = "Self"` trick (https://github.com/serde-rs/serde/issues/1220) which allows
+/// the `remote = "Self"` trick (<https://github.com/serde-rs/serde/issues/1220>) which allows
 /// to directly serialize/deserialize the original fields and combine it with validation.
 /// However, this would lead to nested serialization of the `CsMatrix` and `SparsityPattern`
 /// types. Instead, we decided that we want a more human-readable serialization format using

nalgebra-sparse/src/csc/csc_serde.rs

@@ -4,7 +4,7 @@ use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 /// This is an intermediate type for (de)serializing `CscMatrix`.
 ///
 /// Deserialization requires using a `try_from_*` function for validation. We could have used
-/// the `remote = "Self"` trick (https://github.com/serde-rs/serde/issues/1220) which allows
+/// the `remote = "Self"` trick (<https://github.com/serde-rs/serde/issues/1220>) which allows
 /// to directly serialize/deserialize the original fields and combine it with validation.
 /// However, this would lead to nested serialization of the `CsMatrix` and `SparsityPattern`
 /// types. Instead, we decided that we want a more human-readable serialization format using

nalgebra-sparse/src/csr/csr_serde.rs

@@ -4,7 +4,7 @@ use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 /// This is an intermediate type for (de)serializing `CsrMatrix`.
 ///
 /// Deserialization requires using a `try_from_*` function for validation. We could have used
-/// the `remote = "Self"` trick (https://github.com/serde-rs/serde/issues/1220) which allows
+/// the `remote = "Self"` trick (<https://github.com/serde-rs/serde/issues/1220>) which allows
 /// to directly serialize/deserialize the original fields and combine it with validation.
 /// However, this would lead to nested serialization of the `CsMatrix` and `SparsityPattern`
 /// types. Instead, we decided that we want a more human-readable serialization format using

nalgebra-sparse/src/io/matrix_market.rs

@@ -499,7 +499,7 @@ mod internal {
         fn from_i128(i: i128) -> Result<Self, MatrixMarketError>;
         /// When matrix is a Real matrix, it will convert a [f64] number to this type.
         fn from_f64(f: f64) -> Result<Self, MatrixMarketError>;
-        /// When matrix is a Complex matrix, it will convert a [Complex<f64>] number to this type.
+        /// When matrix is a Complex matrix, it will convert a [`Complex<f64>`] number to this type.
         fn from_c64(c: Complex<f64>) -> Result<Self, MatrixMarketError>;
         /// When matrix is a Pattern matrix, it will convert a unit type [unit] to this type.
         fn from_pattern(p: ()) -> Result<Self, MatrixMarketError>;

nalgebra-sparse/src/lib.rs

@@ -27,7 +27,7 @@
 //!
 //! [Matrix market format support]: io/
 //! [proptest strategies]: proptest/
-//! 
+//!
 //! ## Current state
 //!
 //! The library is in an early, but usable state. The API has been designed to be extensible,

nalgebra-sparse/src/pattern/pattern_serde.rs

@@ -4,7 +4,7 @@ use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 /// This is an intermediate type for (de)serializing `SparsityPattern`.
 ///
 /// Deserialization requires using a `try_from_*` function for validation. We could have used
-/// the `remote = "Self"` trick (https://github.com/serde-rs/serde/issues/1220) which allows
+/// the `remote = "Self"` trick (<https://github.com/serde-rs/serde/issues/1220>) which allows
 /// to directly serialize/deserialize the original fields and combine it with validation.
 /// However, this would lead to nested serialization of the `CsMatrix` and `SparsityPattern`
 /// types. Instead, we decided that we want a more human-readable serialization format using

src/base/rkyv_wrappers.rs

@@ -1,4 +1,4 @@
-//! Wrapper that allows changing the generic type of a PhantomData<T>
+//! Wrapper that allows changing the generic type of a `PhantomData<T>`
 //!
 //! Copied from <https://github.com/rkyv/rkyv_contrib> (MIT-Apache2 licences) which isn’t published yet.
 

tests/macros/trybuild/stack_incompatible_block_dimensions.stderr

@@ -5,9 +5,9 @@ error[E0277]: the trait bound `ShapeConstraint: SameNumberOfColumns<Const<2>, Co
    |            ^^^ the trait `SameNumberOfColumns<Const<2>, Const<3>>` is not implemented for `ShapeConstraint`
    |
    = help: the following other types implement trait `SameNumberOfColumns<D1, D2>`:
-             <ShapeConstraint as SameNumberOfColumns<D, D>>
-             <ShapeConstraint as SameNumberOfColumns<D, Dyn>>
-             <ShapeConstraint as SameNumberOfColumns<Dyn, D>>
+             `ShapeConstraint` implements `SameNumberOfColumns<D, D>`
+             `ShapeConstraint` implements `SameNumberOfColumns<D, Dyn>`
+             `ShapeConstraint` implements `SameNumberOfColumns<Dyn, D>`
    = note: this error originates in the macro `stack` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0282]: type annotations needed
@@ -27,11 +27,6 @@ error[E0599]: no method named `generic_view_mut` found for struct `Matrix<_, Con
 12 | |            a21, a22];
    | |____________________^ method not found in `Matrix<_, Const<3>, _, _>`
    |
-  ::: src/base/matrix_view.rs
-   |
-   |        generic_slice_mut => generic_view_mut,
-   |                             ---------------- the method is available for `Matrix<_, Const<3>, _, _>` here
-   |
    = note: the method was found for
            - `Matrix<T, R, C, S>`
    = note: this error originates in the macro `stack` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/macros/trybuild/stack_incompatible_block_dimensions2.stderr

@@ -5,9 +5,9 @@ error[E0277]: the trait bound `ShapeConstraint: SameNumberOfRows<Const<1>, Const
    |                 ^^^ the trait `SameNumberOfRows<Const<1>, Const<2>>` is not implemented for `ShapeConstraint`
    |
    = help: the following other types implement trait `SameNumberOfRows<D1, D2>`:
-             <ShapeConstraint as SameNumberOfRows<D, D>>
-             <ShapeConstraint as SameNumberOfRows<D, Dyn>>
-             <ShapeConstraint as SameNumberOfRows<Dyn, D>>
+             `ShapeConstraint` implements `SameNumberOfRows<D, D>`
+             `ShapeConstraint` implements `SameNumberOfRows<D, Dyn>`
+             `ShapeConstraint` implements `SameNumberOfRows<Dyn, D>`
    = note: this error originates in the macro `stack` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0282]: type annotations needed
@@ -27,11 +27,6 @@ error[E0599]: no method named `generic_view_mut` found for struct `Matrix<_, _,
 13 | |            a21, a22];
    | |____________________^ method not found in `Matrix<_, _, Const<4>, _>`
    |
-  ::: src/base/matrix_view.rs
-   |
-   |        generic_slice_mut => generic_view_mut,
-   |                             ---------------- the method is available for `Matrix<_, _, Const<4>, _>` here
-   |
    = note: the method was found for
            - `Matrix<T, R, C, S>`
    = note: this error originates in the macro `stack` (in Nightly builds, run with -Z macro-backtrace for more info)